A while back I won a 50ft Python water changer and I was reading the label and I want to say the instructions on the Python said to make 10% weekly or monthly water changes...lol...Wow.....As LTB posted-Gotta be careful with some of the instruction on package labels...some can be misleading at best.....Just look at some of the pictures on aquarium boxes..talk about poor stocking and overstocking....lol....

I have just moved my betta from a 1g to a 2.5g and there is conflicting information on how often I should change the water.(SNIP)

What would you do? I don't know who to trust.

What you should do is buy a test kit so you can actually understand what's going on in your tank's water. You should test ammonia, nitrites, and nitrates a couple times a week for at least a few months while you're getting the hang of it. Remember: if there's nothing wrong with the water, it's not urgent to change it. The only way to know whether it needs a change is to test it.

If ammonia starts to creep up, do a 50% water change (even if it's early), and add some API Quick Start. (You should add some Quick Start now to get the tank cycle started.) Otherwise, if things are testing good, just do a 20% or so water change once a week as a matter of general good practice.

Unless the water gets VERY bad, don't do a 100% change, ever. It could be a shock to the fish. Even if something is very wrong, don't do a 100% change, do a 50% change and follow it a few hours later by another 50% change and test everything again to see if the water is good enough or if it needs another 50% change a few hours later.

I am assuming that your new 2.5g tank is heated and filtered. If not, it should be.

I won several times with Tetra co. and with the aquarium fish magazine in the rewards section, however, that aquarium magazine has since stopped the hard copy and I don't think they have the rewards thing on their online magazine. I get e-mails from Tetra and marineland to enter for free stuff by getting on their mailing list and doing reviews on products...I bet I have won at least $500.00 or more in aquarium products over the past 2-3 years.

Sorry we hijacked your thread fishy...hope you don't mind....

I now have 3 Pythons....2-50ft and 1-100ft or 125ft...I use the 125ft to drain my tanks by gravity into the yard/garden and use the 50ft to fill the tanks from the sink. If you have a lot of tanks and/or big tank/s the Pythons are great...sure beats carrying buckets...lol....

Except for the small tanks..still gotta use buckets with them and either smaller diameter hoses to siphon or a plastic cup for the stir and dip method....or at least that is how I do mine...using a Python on a small tank would drain it in about 2 seconds...lol....and to use it to fill up could disturb the dirt in my soil based tanks-I have used the Python to top off my 10gal's but that is the smallest I will use them on and that is just for top offs.......lol....

IMO/E-you shouldn't base water changes on test results Alone...due to the DOC's that can also buildup and become problematic. Testing the water is a great way to help you understand what is going on, however, regardless of test results-you are going to do the same thing with abnormal result...Water change....
In some cases the test results can help tell you how much water needs to be changed-but in some case-if you wait for test results...It might be too late.

While having a Freshwater master test kit is a good idea and I do recommend them-Its always a good idea to have a good understanding of not just the tank and source water-but to understand how products you use and how the chemistry interact-the cause and effect, however, IMO-you don't have to have one to successfully keep Bettas or even to Fish-In cycle a tank-True, that without a test kit on hand-some of the process will be a guess-but you can also take water to a fish shop for free test if needed. Test kits can be expensive and confusing-plus you can have user error, skewed results, false results...etc... that not just stress you-but the fish- since you will end up making a lot of unneeded water changes.

As for 100% water changes...I do agree, generally 100% water changes are not needed, however, a lot of hobbyist feel the need to remove all byproducts in the tank-both good and bad for a crystal clear/clean tank due to the poor understanding of how the system works and for some it is easier. Making 100% can be safely made-provided that you re-acclimate the Betta to both chemistry and temp properly.

IMO/E-filters are optional for this species-especially in the smaller tanks(under 5gal)-With some of the Long fin males the water movement can be the cause of fin damage and stress.
Without a filter it will be hard if not impossible to establish the nitrogen cycle due to their limiting factors.
You can established the nitrogen cycle in small filtered tanks, however, due to limited surface area-the cycle might not be stable-unless you provide more surface area for the BB to colonize. This is why I recommend twice weekly 50% on small filtered tanks (under 5gal) regardless of cycling stage/completeness. This is where a test kit would come in handy too....Base the second 50% weekly water change on test results. But you will always make 1-50% with vacuum in all areas you can reach without moving anything or disruption of plant roots.

I have been told not to do 100%, but I have a question, with live plants in my 5gal tank, the ammonia keeps skyrocketing. I have to change the water every day, and if I use the detoxifier, the pH plummets. I dont understand it!